Olympian's weapon (4)
I believe the answer is:
epee
'olympian's weapon' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for epee that I've seen before include "piece of fencing" , "Foil for riposte" , "Fighting blade" , "Thin fencing sword" , "Fencing weapon" .)